Separating device and method and signal receiving device and method

ABSTRACT

A separating device and method and a signal receiving device and method are presented. The separating device and method receive plural data streams and then separate and extract at least a portion of data from the received data streams. The signal receiving device and method receive plural data streams and then select, separate and extract at least a portion of the data from the data streams. Then the signal receiving device and method apply signal processing to the portion of the data that has been selected, separated and extracted.

This application is a continuation of International Application No.PCT/JP99/02654, filed May 20, 1999.

BACKGROUND OF THE INVENTION

The present invention relates to a separating device and method and asignal receiving device and a signal receiving method, and is suitablyapplied to a signal receiving device for the digital broadcastingsystem.

SUMMARY OF THE INVENTION

In the conventional digital broadcasting system, the transmitting endconducts the compression coding to the video and audio signals of eachprogram with the MPEG2 (Moving Picture Experts Group Phase 2) standard,and by dividing the various kinds of data to be broadcast, such as theobtained compression-coded data, control data and the like into 184 bytesegments and adding a TS (transport stream) header of 4 bytes containingsync code (47H) and PID (packet identification, 13-bits) to its head,forms a 188-byte TS packet.

Furthermore, the transmitting end forms a transport stream bymultiplexing the obtained TS packet for plural programs and the TSpacket storing program information, QPSK (Quadrature Phase ShiftKeying)-modulates these, and sends out the resultant as a digitalbroadcasting signal.

On the other hand, the receiving end receives and demodulates thedigital broadcasting signal, and extracts the TS packets for the programspecified by the user included in the obtained transport stream based onthe PID. Then it decodes video and audio data stored in the TS packetsto display obtained pictures and to give sound from a speaker.

Accordingly, in the digital broadcasting system, while the transmittingend can multiplex audio and video data for plural programs fortransmission, the user can select and watch a desired program from amongthese programs at the receiving end.

However, in the signal receiving device of the digital broadcastingsystem, the device capable of receiving only one sequence of transportstream is used as a demultiplexer to extract the TS packets for aspecified program from the transport stream obtained by demodulating thedigital broadcasting signal.

For this reason, when plural sequences of digital broadcast signals arereceived, an application in the signal receiving device for displayingpictures of plural programs on the multi-screen needs the same number ofdemultiplexers as there are digital broadcasting signals. Therefore,this causes the problem of increasing circuit size.

Accordingly, the conventional signal receiving device has the problem inthat it is difficult to improve its operability while minimizing itssize. For example, it is difficult to make an efficient application fordisplaying without increasing the circuit size.

The present invention has been done considering the above point andintends to propose a separating device and its method and a signalreceiving device and its method capable of remarkably improving theoperability with a simple structure.

To obviate such problems according to the present invention, theseparating device provides a selecting means for receiving plural datastreams formed of plural program data multiplexed per a fixed unit of188 bytes and selecting a corresponding part or all of the data streamsfrom among the received plural data streams, and a separating/extractingmeans for separating/extracting program data of a specified programincluded in each data stream selected by the selecting means.

As a result, this separating device can extract program data of adesired program from among plural data streams formed by multiplexingplural programs, and for example, it can make an application efficientwith a simple structure in the signal receiving device.

Furthermore, according to the present invention, the separating methodcomprises a first step of receiving plural data streams formed of pluralprogram data multiplexed per the fixed unit and of selecting acorresponding part or all of data streams from among the received pluraldata streams and a second step of separating/extracting program data ofa specified program included in each data stream selected at the firststep.

As a result, this separating method can extract program data of adesired program from among plural data streams formed by multiplexingplural programs, and for example, can easily make an applicationefficient in the signal receiving device.

Furthermore, according to the present invention, the signal receivingdevice comprises a separating means for receiving data streams or datastreams which are formed by multiplexing per the fixed unit pluralprogram data obtained by modulating inputted transmission signals, forselecting a corresponding part or all of data streams from among theplural data streams received, and for separating/extracting program dataof a specified program included in each data stream selected, and asignal processing means for applying prescribed signal processing to thepart or all of the data separated and extracted by the separating meansat the same time.

As a result, this receiving device can extract program data of a desiredprogram from among plural data streams formed by multiplexing pluralprograms and can make an application efficient with a simple structure.

Furthermore, according to the present invention, the signal receivingmethod comprises a first step of receiving input data streams or datastreams which are formed by multiplexing per the fixed unit pluralprogram data obtained by modulating input transmission signals, ofselecting a corresponding part or all of the data streams from among thereceived plural data streams, a second step of separating and extractingprogram data of a specified program included in each data streamselected at the first step, and a third step of applying prescribedsignal processing to the part or all of the data separated and extractedat the second step at the same time.

As a result, this signal receiving method can extract program data ofthe desired program from among plural data streams formed bymultiplexing plural programs and can easily make an applicationefficient.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram showing the structure of a signal receivingdevice according to the present invention.

FIG. 2 is a block diagram showing the structure of a selected-channelextracting unit.

FIG. 3 is a flowchart explaining a processing procedure to extract (a)selected channel(s).

FIG. 4 is a schematic diagram explaining extracting processing to selectone program from each of three transport streams.

FIG. 5 is a schematic diagram explaining extracting processing to selectone program from each of two transport streams.

FIG. 6 is a schematic diagram explaining extracting processing in thecase where the PIDs are identical when selecting one program from eachof two transport streams.

FIG. 7 is a schematic diagram explaining extracting processing to selecttwo programs from one transport stream.

FIG. 8 is a block diagram showing another embodiment.

DETAILED DESCRIPTION

The present invention will be described in detail with reference to theaccompanying drawings.

Structure of Signal Receiving Device according to the Embodiment of thePresent Invention.

In FIG. 1, 1 generally shows a signal receiving device of the digitalbroadcasting system according to the embodiment of the presentinvention. It has first and second receiver systems 3A and 3B connectedrespectively to separate antennae 2A and 2B and can simultaneouslyreceive at least two programs with them under the control of amicroprocessor 4. Note that in FIG. 1, two antennae are provided.However, a signal can be received by one antenna. The signal can bedivided into two signals to be supplied to the first and secondreceiving systems. That is, providing two antennae allows the signalreceiving device to receive digital broadcasting signals from twosatellites. On the other hand, providing one antenna allows the signalreceiving device to select signals that correspond to two transponder ofa digital broadcasting signal from one satellite.

Channel information of a program desired by a user, inputted with aninput unit 5, is supplied to the microprocessor 4 from the input unit 5through a control bus 6. That is, the input unit 5 is an infrared rayreceiving unit, in which the channel information from a remotecontroller (not shown) is input thereto and is supplied to themicroprocessor 4 through the control bus 6.

The microprocessor 4 controls tuners 10A and 10B of the first and thesecond receiver systems 3A and 3B according to the supplied channelinformation based on a program previously stored in a ROM (Read OnlyMemory) 7. Note that, a RAM (Random Access Memory) 8 serves as a memorymeans used for processing of the microprocessor.

As a result, under the control of the microprocessor 4, the tuners 10Aand 10B select the respectively corresponding digital broadcastingsignals from among a plurality of digital broadcasting signals receivedwith the antennae 2A and 2B, and transmit these as selected signals S1Aand S1B to the digital demodulators 11A and 11B, respectively.

The digital demodulators 11A and 11B conduct the digital demodulationprocessing to the supplied selected signals S1A and S1B and transmit theresultant demodulated data D1A and D1B to error correction units 12A and12B, respectively. Then, the error correction units 12A and 12B applythe prescribed error correction processing to the supplied demodulateddata D1A and D1B and transmit the resultant transport stream data(hereinafter, referred to as TS data) D2A and D2B to a selected-channelextracting unit 13.

Under the control of microprocessor 4, the selected-channel extractingunit 13 extracts and multiplexes the TS packet data for pictures and theTS packet data for sound of the specified program from among twosequences of TS data D2A and D2B supplied and the TS data D2C suppliedfrom a digital video tape recorder (VTR) via an IEEE1394 interface 50.Then, the resultant video TS data D3 and audio TS data D4 aretransmitted to an video multi-decode processor 14 and an audio decodeprocessor 15, respectively, or are stored in a RAM 16. Note that, thevideo TS data D3 is a signal generated by multiplexing TS data for oneor plural program(s). In addition, the audio TS data D4 is TS data forone program (for example, a program displayed on a main screen ofprograms displayed on the multi-screen).

Under the control of the microprocessor 4, the video multi-decodeprocessor 14 simultaneously decodes the video TS packet data for one orplural program(s) included in the supplied video TS data D3 with a RAM17 and transmits the resultant video data D5A for one or pluralprogram(s) to a display processor 18.

The display processor 18, under the control of the microprocessor 4,executes the prescribed signal processing with a RAM 19 for multi-screendisplaying, and transmits the obtained display signal S2 to a monitor(not shown) to display pictures based on the display signal S2 on themulti-screen, in the case where pictures of plural programs are includedin the video data D5A. Note that, in the case where pictures of only oneprogram are included in the video data D5A, the prescribed signalprocessing is executed so that the picture can be display on the screenall over as a conventional device.

On the other hand, under the control of the microprocessor 4, audiodecode processor 15 decodes the supplied audio TS packet data D4 with aRAM 20 and then, transmits the resultant audio data D6A to an audioprocessor 21.

Then, under the control of the microprocessor 4, the audio processor 21performs the digital-to-analog conversion on the supplied audio data andoutputs it to the speaker (not shown), or converts the supplied audiodata into an optical digital sound output signal to output. RAM 22 isbidirectionally coupled to the audio processor 21.

In this way, this signal receiving device 1 can display pictures ofplural programs, specified from two different sequences of digitalbroadcasting signals and the TS data obtained via the IEEE1394 interface50 by the user, on the multi-screen by a method of dividing the screen,and at the same time, can give sound of any one of the programs from thespeaker.

On the other hand, when the user manipulates the remote commander tospecify one program and the input unit 5 receives a manipulated signaltransmitted from the remote commander, the microprocessor 4 controlsonly one of the tuners 10A and 10B of the first and second receiversystems 3A and 3B and the IEEE1394 interface 50.

As a result, the selected digital broadcasting signal of the tuner 10Aor 10B of the first or the second receiver system 3A or 3B is subjectedto the demodulating processing and the error correction by the followingdigital demodulator 11A or 11B and error correction unit 12A or 12B torestore the transport stream. Then, the transport stream is supplied tothe selected-channel extracting unit 13 as TS data D2A or D2B. On theother hand, in the case of specifying the digital signal obtained viathe IEEE1394 interface 50, the digital signal obtains TS data D2C in theform of a transport stream. Then, the TS data D2C is supplied to theselected-channel extracting unit 13.

Then, the selected-channel extracting unit 13 separates video TS packetsand audio TS packets for the program specified by the user from the TSdata D2A or D2B or the TS data D2C obtained via the IEEE1394 interface50 under the control of the microprocessor 4. The obtained video TS dataD3 and audio TS data D4 are supplied to the video multi-decode processor14 and audio decode processor 15 respectively.

Then, the video TS data D3, after being decoded by the videomulti-decode processor 14 under the control of the microprocessor 4, isconverted into an analog signal by the display processor 18 and is sentto the monitor as a display signal S2. As a result, the pictures of theprograms specified by the user are displayed on the monitor.

Moreover, the audio TS data D4, after being decoded by the audio decodeprocessor 15 under the control of the microprocessor 4, is converted toan analog signal by the audio processor 21 and transmitted to thespeaker as an audio signal S3. As a result, the sound of the programspecified by the user is given from the speaker.

In this way, signal receiving device 1 can select one sequence of TSdata from among two sequences of TS data D2A and D2B to be given to theselected-channel extracting unit 13 from the first and the secondreceiver systems 3A and 3B and the TS data D2C obtained via the IEEE1394interface 50, to display the pictures and to give sound with respect tothe specified program.

Structure of Selected-channel Extracting unit 13.

In practice, the selected-channel extracting unit 13 is constructed asshown in FIG. 2, in which the TS data D2A and D2B to be suppliedrespectively from the error correction units 12A and 12B of the firstand second receiver systems 3A and 3B are supplied into thecorresponding first or second sync code detecting/interchanging units31A and 31B of the TS selector/multiplexer 30.

The first and second sync code detecting/interchanging units 31A and 31Bdetect sync code stored in the TS header of each TS packet included inthe respectively supplied TS data D2A and D2B, and transmit a sync codedetection signal S10 to a timing controller 32 whenever detecting a synccode.

In addition to this, the first and the second sync codedetecting/interchanging units 31A and 31B rewrite the sync code of eachTS packet to an ID code for internal processing to be given from themicroprocessor 4 through the control bus 6, a control interface 33 andthe timing controller 32 and changes identical PIDs (PacketIdentification) so that the PIDs of TS packets of each program specifiedcan be identified even if the PIDs are the same. Then, these TS packetdata D10A and D10B are sequentially stored in the corresponding firstand the second FIFOs (First-in First-out) 33A and 338.

On the other hand, the timing controller 32, based on the sync codedetection signals S10 supplied from the first and second sync codedetecting/interchanging units 31A and 31B and the control signalsupplied from the microprocessor 4 through the control interface 33,reads out, for example, data in a TS packet unit (in a 188-byte fixedunit) from the first and second FIFOs 33A and 33B alternately with adouble clock frequency, multiplexes the first and second TS data D2A andD2B with a multiplexer 51, and transmits the resultant stream data to aTS separator 34 via the multiplexer 51 as selected/multiplexed data D11,in the case where each of the plural programs specified by the user isincluded in one of two transport streams.

On the other hand, the third sync code detecting/interchanging unit 31Cdetects a sync code stored in the TS header of each TS packet includedin the supplied TS data D2C, and transmits the sync code detectionsignal S10 to the timing controller 32 whenever detecting a sync code.

Further, even when a TS packet included in the input TS data D2C has thesame PID as a TS packet for each program specified by the first andsecond sync code detecting/interchanging unit 31A and 31B, the thirdsync code detecting/interchanging unit 31C rewrites the sync code ofeach TS packet to the identification code for internal processingsupplied from the microprocessor and interchanges the identical PIDs(Packet Identification) so that the PIDs can be identified. Thereafter,it sequentially stores the TS packet data D10C to the correspondingthird FIFO (First-In First-Out) 33C.

The timing controller 32, based on the sync code detection signal 31Csupplied from the third sync code detecting/interchanging unit 31C andthe control signal supplied from the microprocessor 4 through thecontrol interface 33, reads, for example, data in the TS packet unit (ina 188-byte unit) from the first, second and third FIFOs 33A, 33B and 33Calternately with a threefold clock frequency, multiplexes the first,second and third TS data D2A, D2B and D2C with the multiplexer 51, andtransmits the resultant stream of data to the TS separator 34 asselected/multiplexed data D11, in the case where each of plural programsspecified by the user are included in each of three transport streams.

In this case, firstly, the TS separator 34 extracts the TS packet havingthe program information included in the digital broadcasting signalselected at the first and the second receiver systems 3A and 3B from theselected/multiplexed data D11 and the TS packet having the programinformation included in the TS data D2C obtained through the IEEE1394interface 50, and transmits these to the microprocessor 4 through thecontrol interface 33 and the control bus 6 in order.

Then, the microprocessor 4 obtains the PID of each video and audio TSpacket for the program specified based on the program information to besupplied from the TS separator 34 and transmits it to the TS separator34 through the control bus 6 and the control interface 33 in order.

Thus, the TS separator 34 extracts TS packets of such as video, audio,control data and data signal for each program specified from among theselected/multiplexed data D11 based on the PID given from themicroprocessor 4, and transmits the control information and data signalfor each program to the microprocessor 4 via the control interface 33and the same time, transmits the video and audio TS packet data for eachprogram to a PID interchange and sync code conversion unit 35 or storesthem in the RAM 16 through the RAM interface 36, as the video TS packetdata D12A and audio TS packet data D12B.

In this connection, the TS separator 34 can select TS packetscorresponding to the program selected by the user from among the TS dataD2A and D3B received by the first and second receiver system 3A and 3Bto generate new TS data D2C, and can record it on the digital VTRthrough the IEEE1394 interface 50. In this case, the TS separator 34 isto output the relation between the current PID and the former one to thedigital VTR through the IEEE1394 as interchange information when the TSpacket having the PID interchanged exists in the TS data D2C.

Under the control of the microprocessor 4, the PID interchange and synccode conversion unit 35 rewrites the ID code and PID attached by thefirst, second, and third sync code detecting/interchanging units 31A,31B and 31C to original synchronization codes with respect to each videoand audio TS packet of the supplied video TS packet data D12A and audioTS packet data D12B.

Furthermore, in the case where the PIDs of the video and audio TSpackets for plural programs specified by the user are identical, the PIDinterchange and sync code conversion unit 35 transmits information tospecify the channel numbers of TS packets having identical PIDs to thevideo multi-decode processor 14 or to the audio decode processor 15through a control line CONT.

On the other hand, in the case where only one program is specified bythe user with the input unit 5, under the control of the microprocessor4, the timing controller 32 reads out the data in the TS packet unit (ina 188-byte unit) with a normal speed only from the corresponding first,second or third FIFO 33A, 33B or 33C based on the sync code detectionsignal S10 to be given from the corresponding first, second or thirdsync code detecting/interchanging unit 31A, 31B, 31C and transmits thisto the TS separator 34 as the selected/multiplexed data D11.

At this point, the TS separator 34 extracts TS packets having programinformation from the supplied selected/multiplexed data D11, andtransmits these to the microprocessor 4 through the control interface 33and the control bus 6, in order.

Then, the microprocessor 4 obtains the PID of each video and audio TSpacket for programs specified by the user based on the programinformation to be supplied from the TS separator 34, and outputs this tothe TS separator 34 through the control bus 6 and the control interface33 in order.

Thus, the TS separator 34 extracts each TS packet of such as picture,audio, control data and data signal for the specified program from theselected/multiplexed data D11 based on the PID supplied from themicroprocessor 4, and transmits the control information and data signalto the microprocessor 4 through the control interface 33 and the controlbus 6 in order and the same time, transmits data of each TS packet forpicture and sound to the PID interchange and sync code conversion unit35 or stores them in the RAM 16 through the RAM interface 36, as thevideo TS packet data D12A and audio TS packet data D12B.

In the case where only one program is specified by the user, since it isimpossible that PIDs are identical, the PID interchange and sync codeconversion unit 35 does not interchange a PID. Therefore, the PIDinterchange and sync code conversion unit 35 transmits the suppliedvideo TS packet data D12A to the video multi-decode processor 14 as thevideo TS packet stream data D3 as it is and transmits the supplied audioTS packet data D12B to the audio decode processor 15 as the audio TSpacket stream data D4 as it is, under the control of the microprocessor4.

In this way, the selected-channel extracting unit 13 can select andoutput the video and audio TS packets for one or more programs specifiedfrom the TS data D2A and D2B supplied from the error correcting units12A and 12B in the first and second receiver systems 3A and 3Brespectively and the TS data D2C supplied through the IEEE1394 interface50.

FIG. 3 shows a processing procedure of extracting a selected channel inthe selected-channel extracting unit 13. The selected-channel extractingunit 13 controlled by the microprocessor 4 enters the processingprocedure in step SP10, and then judges the number of programs specifiedby the user at following step SP11. When one program is specified, theselected-channel extracting unit 13 proceeds to step SP13 to perform aselection and a decoding error correction by controlling one receiversystem (out of the first and second receiver systems 3A and 3B and thethird receiver system through the IEEEE1394 interface 50). Note that theIEEE1394 interface 50 also performs the selection and the decoding errorcorrection as required.

Then, the selected-channel extracting unit 13 outputs the resultantvideo TS packet stream data D3 and the audio TS packet stream data D4 tothe video multi-decoder 14 and the audio decoder 15 at step SP16, andterminates the processing procedure at step SP20.

On the other hand, in the case where plural programs are specified atstep SP11, the selected-channel extracting unit 13 proceeds to stepSP12. In the case where the specified programs are included only in theTS data obtained through one of three receiver systems (the first andsecond receiver system 3A and 3B and the third receiver system throughthe IEEE1394 interface 50), the selected-channel extracting unit 13obtains a negative result at step SP12. Then, it proceeds to step SP14to perform the selection and the decoding error correction bycontrolling one receiver system (out of the first and second receiversystems 3A and 3B and the third receiver system through the 1EEE1934interface 50). In this connection, the IEEE1394 interface 50 alsoperforms the selection and the error correction as required.

After that, the selected-channel extracting unit 13 outputs theresultant video TS packet stream data D3 and the audio TS packet streamdata D4 to the video multi-decoder 14 and the audio decoder 15 at stepSP16, and terminate the processing procedure at step SP20.

On the other hand, when a positive result is obtained at step SP12, thatis, when the programs specified by the user are included in TS dataobtained by two or more receiver systems (two or more out of the firstand second receiver systems 3A and 3B and the third receiver systemthrough the IEEE1394 interface 50), the selected-channel extracting unit13 obtains the positive result at step SP12. Then it proceeds to stepSP15 to perform the selection and the error correction by controllingtwo or more receiver systems (two or more out of the first and secondreceiver systems and the third receiver system through the IEEE1394interface 50) having the TS data specified.

After that, the selected-channel extracting unit 13 proceeds thefollowing step SP17 to judge whether or not there are identical PIDs inthe selected TS packets. When identical PIDs exist, it proceeds to stepSP18 to interchange the PIDs. On the other hand, the selected-channelextracting unit proceeds to step SP19 when identical PIDs do not exist.

The selected-channel extracting unit 13 outputs the video TS packetstream data D3 and the audio TS packet stream data D4 to the videomulti-decoder 14 and the audio decoder 15 at step SP19, and thenterminates the processing procedure at step SP20.

According to the above-mentioned structure, in the case of selecting oneprogram from each of digital broadcasting signals and the TS datareproduced from the digital VTR D2A (FIG. 4(A)), D2B (FIG. 4(B)) and D2C(FIG. 4(C)) respectively corresponding to the specified programs in thefirst and second receiver systems 3A and 3B and the third receiversystem for receiving TS data through the IEEE1394 interface 50 as shownin FIG. 4, the receiving device 1 reads three TS data D2A, D2B and D2Cfrom the FIFOs with the timing controller 32 with a threefold clock. Andthese data becomes data compressed in a temporal axis direction as shownin FIG. 4(D).

TS separator 34 extracts only TS packets having video data for theselected program, extracting the TS packets (PID=3) for channel 2included in the first TS data D2A, the TS packets (PID=15) for channel 6included in the second TS data D2B, and the TS packets (PID=23) forchannel 8 included in the third TS data D2C, as shown in FIG. 4(E).

In addition, at this time, the TS separator 34 extracts the TS packetshaving one piece of audio data for the specified program, extracting theTS packets (PID=4) for channel 2 included in the first TS data D2A, forexample, as shown in FIG. 4(F).

In this way, one program is selected from each of 3 pieces of TS dataD2A, D2B, and D2C received by the first, second and third receiversystems. The pictures of the three programs can be displayed on thedisplay. The sound of one program out of the three programs can beplayed.

In this case, for example, the screen of the display formed of the CRT(Cathode Ray Tube) displays the picture of each program in one area outof three areas that the screen is divided into. The sound of one programout of the displayed programs is given from the speaker provided in thedisplay unit.

On the contrary, in the case where the user selects programs eachincluded in the TS data D2A or D2B obtained through the two receiversystems (for example, the first receiver system 3A and the secondreceiver system 3B) out of three receiver systems, the two pieces of TSdata D2A (FIG. 5(A)) and D2B (FIG. 5(B)) are read out from the FIFOswith a double clock by the timing controller 32 as shown in FIG. 5.These data are multiplexed as data compressed in the temporal axisdirection as shown in FIG. 5(C) and then, are supplied to the TSseparator 34.

Then, the TS separator 34, by extracting only the TS packets havingvideo data for the selected programs, extracts the TS packets (PID=3)for channel 2 included in the fist TS data D2A and the TS packets(PID=15) for channel 6 included in the second TS data D2B, for example,as shown in FIG. 5(D).

Further, at this time, the TS separator 34, by extracting the TS packetshaving audio data for one of the selected programs, extracts the TSpackets (PID=4) for channel 2 included in the first TS data D2A, forexample, as shown in FIG. 5(E).

In this way, one program can be selected from each of two pieces of TSdata D2A and D2B received by the first and second receiver system, andthe pictures of the total two programs and the sound of one program outof two can be displayed at the display.

In this case, the picture of each program is displayed in one area oftwo areas that the screen in divided into, and the sound of one programout of the displayed programs can be given from the speaker provided atthe display unit.

Furthermore, on the contrary, when the user selects a program from eachof TS data D2A and D2B obtained by two receiver systems (for example,the first receiver system 3A and the second receiver system 3B) out ofthe three receiver systems, if TS packets having the identical PIDsexist in the selected two TS data D2A and D2B, the two TS data D2A (FIG.6(A)) and D2B (FIG. (B)) are read out from the FIFOs with the doubleclock by the timing controller 32 and then are multiplexed as datacompressed in the temporal axis direction as shown in FIG. 6(C). In thiscase, the sync code detecting/interchanging unit 31B has interchangedthe PID of the TS packet in the second TS data D2B, which was the sameas that in the first TS data D2A, so that the PIDs of the TS packet forthe channel 4 in the second TS data D2B has been changed from “PID=3” to“PID=a”, as shown in FIG. 6(C). In this way, the TS data D2B having thechanged PID of the TS packet and the TS data D2A having the original PIDare multiplexed by the multiplexer 51, to obtain a sequence of TSpackets having PIDs different from each other, as shown in FIG. 6(C).This sequence of TS packets is supplied to the TS separator 34.

Then the TS separator 34 extracts only the TS packets having video datafor the selected program to extract the TS packets (PID=3) for channel 2included in the first TS data D2A and the TS packet (PID=7(e)) forchannel 6 included in the second TS data D2B, for example, as shown inFIG. 6(D).

In addition, at this time, the TS separator 34 extracts the TS packethaving audio data for one program out of the selected ones to extractthe TS packets (PID=8(f)) for channel 6 included in the first TS dataD2A, for example, as shown in FIG. 6(E).

In this way, one program can be selected from each of two pieces of TSdata D2A and D2B received by the fist and second receiver systems, thepictures of the total two programs and the sound of one program out ofthem can be displayed at the display.

In this case, the picture of each program is displayed in one area outof two areas which the screen is divided into, and the sound of oneprogram out of them being displayed is given from the speaker providedat the display.

Furthermore, on the contrary, in the case where the user selects twoprograms included in the TS data D2A obtained by one receiver system(for example, the first receiver system 3A) of the three receiversystems, as shown in FIG. 7, one piece of TS data D2A (FIG. 7(A)) isread out from the FIFO with a normal clock by the timing controller 32,and is supplied to the TS separator 34 as data non-compressed in thetemporal axis direction as shown in FIG. 7(B).

Then, the TS separator 34 extracts only the TS packets having video datafor the selected programs to extract the TS packets (PID=3) for channel2 included in the first TS data D2A and the TS packets (PID=5) forchannel 3 included in the first TS data D2A as shown in FIG. 7(C), forexample.

In addition, at this time, the TS separator 34 extracts the TS packetshaving audio data for one program out of the selected programs toextract the TS packets (PID=6) for channel 3 included in the first TSdata D2A, for example, as shown in FIG. 7(D).

In this way, two programs are selected from the one piece of TS data D2Areceived by the first receiver system, the pictures of the two programscan be displayed at the display unit, and the sound of one program outof the two can be played.

In this case, the picture of each program is displayed in one area oftwo areas which the screen is divided into and the sound of one programout of the programs being displayed are given from the speaker providedat the display unit.

In this way, in the case where the user specifies plural programs, thereceiving device 1 selects a digital broadcasting signal or the TS datareproduced from the digital VTR corresponding to the specified programin the first and second receiver systems 3A and 3B and the thirdreceiver system for receiving TS data through the IEEE1394 interface 50,sequentially performs the demodulating and the error correctionprocessing with the corresponding digital demodulator and the errorcorrection unit, and then separates and extracts video TS packets forone or more program(s) and audio TS packets for one program specified bythe obtained first, second and third TS data D2A, D2B and D2C.

After that, the obtained video TS packet data D3 for plural programs aresimultaneously decoded by the video multi-decode processor 14 and theaudio TS packet data D4 for one program is decoded by the audio decodeprocessor 15.

In addition, the pictures for plural programs specified based on theobtained video data D5A and D6A are subjected to signal processing fordisplay on multi-screen by the display processor 18, and the sound ofthe specified program is selected by the audio processor 21.

Thus, the receiving device 1 can receive plural programs from the pluraldigital broadcasting signals and can display them on multi-screen,thereby making it possible to have a high function with respect todisplay on a screen.

Further, in the receiving device 1, the selected-channel extracting unit13 can separate the TS packets for programs specified by the user fromthe TS data D2A, D2B, and D2C correspondingly to the inputs of pluralityof TS data D2A, D2B and D2C, so that it is not necessary to provideplural demultiplexers for extracting TS packets for a program specifiedby the transport stream, thereby making it possible to construct itsimply.

According to the above-mentioned structure, the TS data D2A, D2B, D2Coutput from the first, second, third receiver systems are selected bythe selected-channel extracting unit 13 as required, the TS packetshaving various kinds of data such as pictures and sound for a specifiedprogram included in the selected TS data D2A, D2B and D2C are separatedand extracted, thereby making it possible to make an applicationefficient with a simple structure. Thus, it is possible to significantlyimprove its function with a simple structure.

Note that, in the aforementioned embodiment, two antennae are provided.However, as shown in FIG. 8, a signal from one antenna 2C can be dividedinto two signals by a divider 40, and be supplied to the first andsecond receiver systems. That is, in the case of providing two antennas,digital broadcasting signals from two satellites can be received, and inthe case of providing only one antenna, a signal corresponding to twotransponders in the digital broadcasting signal from one satellite canbe selected.

Further, in the embodiment described above, the selected-channelextracting unit 13 is constructed as a separating device according tothe present invention as shown in FIG. 2. However, the present inventionis not only limited to this but various kinds of structures can beapplied as the structure of the selected-channel extracting unit 13 aslong as the data of the specified sequences can be separated andextracted from the data stream generated by multiplexing pluralsequences of data in a prescribed unit.

In this case, in the embodiment described above, the TSselector/multiplexer 30 is comprised of the first, second and third synccode detecting/interchanging units 31A, 31B and 31C, the FIFOs 33A, 33B,and 33C, and the timing controller 32 as the selecting means forreceiving plural data streams and selecting the corresponding part orall of the data streams from among the received plural data streams, asshown in FIG. 2. However, the present invention is not limited theretoand other various kinds of structures can be applied.

Furthermore, in the embodiment described above, the TS separator 34serving as the separating/extracting means for separating and extractingdata (video data and audio data) of the sequences specified by the user(pictures and sound of the specified program) included in the TS dataD2A, D2B and D2C is placed at the stage following the FIFOs 33A, 33B and33C and the timing controller 32, the multiplexer 51 serving as themultiplexing means for multiplexing these data. However, the presentinvention is not only limited to this but also the TS separator 34 canbe placed at the stage preceding the FIFOs 33A, 33B, 33C, the timingcontroller 32 and the multiplexer 51, and the same effects as the aboveembodiment can be obtained.

Furthermore, in the embodiment described above, the selected-channelextracting unit 13 multiplexes and outputs video and audio data for theprograms specified by the user in the form of a TS packet. However, thepresent invention is not only limited to this but also video and audiodata for the programs specified by the user can be multiplexed andoutput in the form of a signal, such as ES (Elementary Stream) and PES(Packetized Elementary Stream). In this case, the signal receivingdevice can be so constructed that the selected-channel extracting unit13 outputs a control signal so as to make the video multi-decodeprocessor 14 and the audio decode processor 15 decide what program thevideo TS data D3 and audio TS data D4 to be supplied at that momentbelong to.

Furthermore, in the embodiment described above, the selected-channelextracting unit 13 is constructed so as to cope with the inputs of threetransport streams. However, the present invention is not only limited tothis but also, the selected-channel extracting unit 13 can cope withfour or more transport streams as long as it is constructed so as toreceive plural data streams, to select corresponding part or all datastreams from among the received plural data streams, and to separate andextract data of a specified sequence included in the selected datastreams.

Furthermore, in the embodiment described above, identical PIDs of TSpackets are interchanged. However, the present invention is not limitedthereto but also, for example, with respect to a TS packet havinganother identical PID, a flag to specify the channel number can be addedto its header to output the TS packet from the selected-channelextracting unit 13 through a control line CONT.

Furthermore, in the embodiment described above, the receiving deviceaccording to the present invention is applied to a receiving device in adigital broadcasting system. However, the present invention is notlimited thereto but also can be applied to other various types ofreceiving device such as a receiving device for cable televisionbroadcasting. In this case, a program of a different broadcasting systemcan be extracted by making a receiver system cope with the differentbroadcasting system (for example, CS (Communications Satellite)broadcasting for distributing programs via a communication satellite, BS(Broadcasting Satellite) broadcasting for distributing program via abroadcasting satellite), cable television broadcasting, or digitalbroadcasting for distributing with a ground wave).

1. An apparatus for receiving, separating and decoding a data stream,comprising: a receiver operable to produce an initial data streamcontaining multiplexed data packets representing a plurality of dataprograms from at least one signal received over a communication channel,the multiplexed data packets each including an original packetidentifier; a separating device operable to produce an intermediate datastream containing multiplexed data packets representing one or moreselected ones of the data programs chosen from the initial data stream,the separating device including: a multiplexer operable to produce amultiplexed data stream including the initial data stream, a separatoroperable to extract the selected data programs from the multiplexed datastream, and an interchange unit operable to change the original packetidentifier of a first multiplexed data packet to a unique packetidentifier when the original packet identifier of the first multiplexeddata packet is identical to the original packet identifier of a secondmultiplexed data packet, and to rewrite the unique packet identifier ofthe first multiplexed data packet back to the original packet identifierof the first multiplexed data packet prior to the separating deviceproducing the intermediate data stream; and a decode processor operableto decode the intermediate data stream such that the multiplexed datapackets representing the selected data programs are associated with oneanother.
 2. An apparatus for receiving, separating and decoding a datastream, comprising: a receiver operable to produce an initial datastream containing multiplexed data packets representing a plurality ofdata programs from at least one signal received over a communicationchannel, the multiplexed data packets each including an original packetidentifier; a separating device operable to produce an intermediate datastream containing multiplexed data packets representing one or moreselected ones of the data programs chosen from the initial data stream,the separating device including: a separator operable to extract theselected data programs from the initial data stream, a multiplexeroperable to produce a multiplexed data stream including each of theselected data programs extracted by the separator, and an interchangeunit operable to change the original packet identifier of a firstmultiplexed data packet to a unique packet identifier when the originalpacket identifier of the first multiplexed data packet is identical tothe original packet identifier of a second multiplexed data packet, andto rewrite the unique packet identifier of the first multiplexed datapacket back to the original packet identifier of the first multiplexeddata packet prior to the separating device producing the intermediatedata stream; and a decode processor operable to decode the intermediatedata stream such that the multiplexed data packets representing theselected data programs are associated with one another.
 3. An apparatusfor inputting an initial data stream containing multiplexed data packetsrepresenting a plurality of data programs received over a communicationchannel and for producing an intermediate data stream including one ormore selected data programs the multiplexed data packets each includingan original packet identifier, the apparatus comprising: a multiplexeroperable to produce a multiplexed data stream including the initial datastream and the one or more selected data programs; a separator operableto extract the selected data programs from the multiplexed data stream;and an interchange unit operable to change the original packetidentifier of a first multiplexed data packet to a unique packetidentifier when the original packet identifier of the first multiplexeddata packet is identical to the original packet identifier of a secondmultiplexed data packet, and to rewrite the unique packet identifier ofthe first multiplexed data packet back to the original packet identifierof the first multiplexed data packet prior to producing the intermediatedata stream.
 4. The apparatus of claim 3, wherein the interchange unitincludes: a first interchange unit operable to change the originalpacket identifier of the first multiplexed data packet to the uniquepacket identifier when the original packet identifier of the firstmultiplexed data packet is identical to the original packet identifierof the second multiplexed data packet; and a second interchange unitoperable to rewrite the unique packet identifier of the firstmultiplexed data packet back to the original packet identifier of thefirst multiplexed data packet prior to the separating device producingthe intermediate data stream.
 5. An apparatus for inputting an initialdata stream containing multiplexed data packets representing a pluralityof data programs received over a communication channel and for producingan intermediate data stream including one or more selected ones of thedata programs, the multiplexed data packets each including an originalpacket identifier, the apparatus comprising: a separator operable toextract each of the selected data programs from the initial data stream;a multiplexer operable to produce a multiplexed data stream includingthe selected data programs extracted by the separator; and aninterchange unit operable to change the original packet identifier of afirst multiplexed data packet to a unique packet identifier when theoriginal packet identifier of the first multiplexed data packet isidentical to the original packet identifier of a second multiplexed datapacket, and to rewrite the unique packet identifier of the firstmultiplexed data packet back to the original packet identifier of thefirst multiplexed data packet prior to producing the intermediate datastream.
 6. The apparatus of claim 5, wherein the interchange unitincludes: a first interchange unit operable to change the originalpacket identifier of the first multiplexed data packet to the uniquepacket identifier when the original packet identifier of the firstmultiplexed data packet is identical to the original packet identifierof the second multiplexed data packet; and a second interchange unitoperable to rewrite the unique packet identifier of the firstmultiplexed data packet back to the original packet identifier of thefirst multiplexed data packet prior to the separating device producingthe intermediate data stream.
 7. A method for decoding packet data,comprising: producing an initial data stream containing multiplexed datapackets representing a plurality of data programs from at least onesignal received over a communication channel, the multiplexed datapackets each including an original packet identifier; producing anintermediate data stream containing multiplexed data packetsrepresenting one or more selected ones of the data programs chosen fromthe initial data stream, the step of producing the intermediate datastream including: producing a multiplexed data stream including theinitial data stream, extracting the selected data programs from themultiplexed data stream, changing the original packet identifier of afirst multiplexed data packet to a unique packet identifier when theoriginal packet identifier of the first multiplexed data packet isidentical to the original packet identifier of a second multiplexed datapackets, and rewriting the unique packet identifier of the firstmultiplexed data packet back to the original packet identifier of thefirst multiplexed data packet prior to producing the intermediate datastream; and decoding the intermediate data stream such that themultiplexed data packets representing the selected data programs areassociated with one another.
 8. A method for decoding packet data,comprising: producing an initial data stream containing multiplexed datapackets representing a plurality of data programs from at least onesignal received over a communication channel, the multiplexed datapackets each including an original packet identifier; producing anintermediate data stream containing multiplexed data packetsrepresenting one or more selected ones of the data programs chosen fromthe initial data stream, the step of producing the intermediate datastream including: extracting the selected data programs from the initialdata stream, producing a multiplexed data stream including each of theextracted data programs, changing the original packet identifier of afirst multiplexed data packet to a unique packet identifier when theoriginal packet identifier of the first multiplexed data packet isidentical to the original packet identifier of a second multiplexed datapacket, and rewriting the unique packet identifier of the firstmultiplexed data packet back to the original packet identifier of thefirst multiplexed data packet prior to producing the intermediate datastream; and decoding the intermediate data stream such that themultiplexed data packets representing each of the one or more selecteddata programs are associated with one another.
 9. A method of producingan intermediate data stream from an initial data stream containingmultiplexed data packets representing a plurality of data programsreceived over a communication channel, the intermediate data streamincluding one or more selected ones of the data programs, and themultiplexed data packets each including an original packet identifier,the method comprising: producing a multiplexed data stream including theinitial data stream and the one or more selected data programs;extracting the selected data programs from the multiplexed data stream;changing the original packet identifier of a first multiplexed datapacket to a unique packet identifier when the original packet identifierof the first multiplexed data packet is identical to the original packetidentifier of a second multiplexed data packet; and rewriting the uniquepacket identifier of the first multiplexed data packet back to theoriginal packet identifier of the first multiplexed data packet prior toproducing the intermediate data stream.
 10. A method of producing anintermediate data stream from an initial data stream containingmultiplexed data packets representing a plurality of data programsreceived over a communication channel, the intermediate data streamincluding one or more selected ones of the data programs, and themultiplexed data packets each including an original packet identifier,the method comprising: extracting each of the selected data programsfrom the at least one initial data stream; producing a multiplexed datastream including the extracted data programs; changing the originalpacket identifier of a first multiplexed data packet to a unique packetidentifier when the original packet identifier of the first multiplexeddata packet is identical to the original packet identifier of a secondmultiplexed data packet; and rewriting the unique packet identifier ofthe first multiplexed data packet back to the original packet identifierof the first multiplexed data packet prior to producing the intermediatedata stream.